First off - Make that "desperate". Sorry. Second, an update..
I've modified remote.c in gdb to print the data coming across the serial line. When I boot with -d and enter "gdb" followed by "s", absolutely nothing comes across the serial line - readchar times out every time. If I then reboot without -d (with the same modified gdb running) and set console=comconsole I see all of the expected console characters read by readchar. So it appears that the gdb stub on the target isn't outputing any data to the serial line whatsoever. Again, I have KDB, DDB, and GDB set in the configuration file and the sio flags set to 0x90 (I've tried 0xc0 as well) in the loader.conf file. Furthermore, when I boot with -d I see the message: GDB: Current port: sio Can anyone think of a reason why the target isn't outputting debug packets to the serial port? Can anyone suggest a method to debug a debugger? Thanks ----- Original Message ----- From: Peter Craft To: freebsd-questions@freebsd.org Sent: Friday, February 20, 2009 3:28 PM Subject: KGDB connection failure - Please help, I'm desparate! I've been trying for three days to get KGDB to work. I've followed the instructions here: http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/kerneldebug-online-gdb.html and here: http://www.lemis.com/grog/Papers/Debug-tutorial/tutorial.pdf without success. Specifically, I've rebuilt my kernel with: makeoptions DEBUG=-g # Build kernel with gdb(1) debug symbols .. options KDB options DDB options GDB My "boot.config" file contains -P and my /boot/loader.conf file contains: hint.sio.0.flags="0x90" When I issue the "boot -d" on the target, the system breaks in to the "db" prompt as expected, at which point I enter "gdb" followed by "s". All of which seems to work perfectly. On the debugger side I enter kgdb with "kgdb -r /dev/cuad0 -v kernel.debug" from the build directory and I get: Ignoring packet error, continuing... Ignoring packet error, continuing... Ignoring packet error, continuing... Couldn't establish connection to remote target Malformed response to offset query, timeout If I boot the remote system with "set console=comconsole", I'm able to communicate across the serial line as a console, so I believe that the serial ports and cable are functioning properly. I just can't get gdb to connect. Can anyone offer any suggestion on what to try next? Or tips on how to go about debugging the problem? This is with FreeBSD 7.1. Thanks in advance, Pete _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"